The present invention relates to the field of spinal osteosynthesis surgery. More specifically, it relates to a vertebral osteosynthesis plate intended to immobilise at least two adjacent vertebrae in relation to each other.
Such plates are generally cut out of a rigid or flexible biocompatible material, particularly metal, for example titanium. They comprise circular or oblong slots to insert fixation screws or vertebral implants formed by a threaded device.
For example, the French patent applications FR 2763828 or FR 2766353 disclose vertebral osteosynthesis systems using plates known in the prior art.
The French patent application FR 2737402, which discloses a prior cervical spine stabilisation device, intended to fix the vertebrae and restore a normal interbody space is also known. The system comprises a double curve rectangular plate, equipped with ovoid slots, and corporeal anchoring screws, and threaded locking plugs housed in the threading provided in the top part of the anchoring screw.
These osteosynthesis plates according to the prior art are difficult to fit. Indeed, the surgeon starts by correcting the spinal alignment with a temporary correction instrument comprising correction rods intended to be attached in the vertebrae, which obstruct the fitting of the plate and its fixation. If the correction instrument is removed before the definitive fixation of the plate, it is necessary to make adjustments of the plate alignment before the definitive fixation.
To remedy this drawback, the German patent application No. DE 4 201 043 proposed a vertebral osteosynthesis plate of a general rectangular shape comprising at least four slots to insert fixation means and two longitudinal slits opening onto a transversal edge of the plate, to enable positioning and definitive fixation of the plate with no prior removal of the relative vertebral orientation correction instrument.
The major drawback of this plate lies in the fact that the surgeon is obliged to make six holes: two holes to enable the use of the relative vertebral orientation correction instrument and four holes to attach the vertebral osteosynthesis plate.
In addition, the presence of longitudinal slits makes it necessary to increase the width of the osteosynthesis plate.